Batteries including a non-aqueous electrolyte secondary battery, a nickel-cadmium battery, and a nickel metal hydride battery are widespread as a power source of mobile electronic equipment such as a mobile phone, a personal computer and a video camera by taking advantage of the characteristics of being compact and lightweight and having high energy density. Nowadays, there is a strong move afoot to upsize such batteries and apply the batteries to large electric equipment for industrial use, such as an electric vehicle. Such batteries are those where a winding type power generating element that strip electrodes are wound via a separator, or a stack type power generating element that flat-plate electrodes are laminated via a separator is housed in a battery case, the battery case is sealed with a battery lid, and a positive terminal and a negative terminal are attached to the exterior of the battery. Commonly used is a configuration where a battery case serves as one electrode terminal and the other electrode terminal is attached to the exterior of the battery in a state of being insulated from the battery case.
However, there is a problem in a conventional battery whose case is electrically connected to a positive or negative electrode, that is, the case has electric continuity. Namely, the battery tends to have a complex configuration for electrically connecting a current collector, the case, and a conductive member such as an electrode terminal while a gap between the case and the conductive member is limited, and a large number of parts.
The present invention has been made considering the above circumstances, and an object thereof is to provide an electric storage device with a simple configuration including a current collector, a case, and a conductive member electrically connected with each other while a gap between the case and the conductive member is limited.